Two light bulbs are marked 230 V; 75 W and 230 V; 150 W. If the first bulb has a resistance R, then the resistance of the second is;

(1/4) R

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(1/2)R

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Solution

The correct option is C
(1/2)R

P = V² /R

For the 1st bulb; R = V² /P₁ = 230² / 75 ......(i)

For the 2nd bulb; R₂ = V² /P₂ = 230² /150 ......(ii)

from, (i) and (ii); R₂ = (1/2) R

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Two light bulbs are marked 230 V; 75 W and 230 V; 150 W. If the first bulb has a resistance R, then the resistance of the second is;

The correct option is C (1/2)R P = V2 /R For the 1st bulb; R = V2 /P1 = 2302 / 75 ......(i) For the 2nd bulb; R2 = V2 /P2 = 2302 /150 ......(ii) from, (i) and (ii); R2 = (1/2) R

The correct option is C
(1/2)R

P = V² /R

For the 1st bulb; R = V² /P₁ = 230² / 75 ......(i)

For the 2nd bulb; R₂ = V² /P₂ = 230² /150 ......(ii)

from, (i) and (ii); R₂ = (1/2) R